Electrophysiological procedures require recording of cardiac electrical activity. An electrophysiology study may provide determination of the location and treatment of arrhythmias including atrial fibrillation, atrial flutter, ventricular arrhythmias, atrial-ventricular (AV) conduction delays or blocks, and paroxysmal supraventricular tachycardia (PSVT).
Two significant heart rhythm disorders amenable to electrophysiology technology are atrial fibrillation (AF) and ventricular tachycardia (VT). Treatment of AF and VT via electrophysiology methods include diagnosing the source of the arrhythmia by locating its origin (“mapping”) and restoring normal heart rhythms by isolating or destroying the arrhythmia causing sites (“ablation”).
One traditional AF surgical procedure, known as the “Maze” procedure, required a surgeon to craft several slices through the wall of the atrium with a scalpel so as to create a conductive scar pattern. While effective in treating AF, this procedure is complicated to perform, highly invasive, and typically associated with bleeding complications resulting in extended hospitalization.
Today, as an alternative to open-heart surgery, many medical procedures are performed using minimally invasive surgical techniques, wherein one or more slender implements are inserted through one or more small incisions into a patient's body. For those procedures using ablation, the surgical implement can include a rigid or flexible structure having an ablation device at or near its distal end that is placed adjacent to the tissue to be ablated. Ablation is typically used to destroy arrhythmia-causing tissue by burning, freezing or surgical removal. Some techniques involve positioning a catheter inside the heart at an arrhythmogenic focus or conduction defect and thermally ablating the heart tissue.
Presently, radio frequency (RF) energy is a popular method for ablation; but it has the potential of destroying healthy coronary structures and creating stenosis when a lesion is created on an artery or vein. Another drawback to the use of RF is that once a physician commences to burn the subject tissue, the procedure is absolute. Once the target focus site is identified, the surgical excision is performed and the procedure is final. No correction is made for mapping errors, nor does it allow for continuous or “progressive” monitoring of the ablation process. Known ablation tools do not allow for enhanced mapping in conjunction with, and as an integral part of, the ablation process.
Therefore, it is desirable to have a method for diagnosing and treating heart and vascular tissue that is minimally invasive and does not cause peripheral damage to healthy tissue and allows for corrections for mapping errors. Furthermore, it is desirable to provide an ablation method to diagnose and treat heart and vascular tissue that is progressive, and may be used in conjunction with known mapping techniques to allow for continuous mapping during the ablation process.